1. Field of the Invention
The present invention relates to a cooled ring carrier assembly. In particular, this invention relates to a cooled ring carrier assembly that allows for a safe and tight welded joint between the ring carrier and a metal sheet cooling duct when the duct is secured on the ring carrier.
2. The Prior Art
A ring carrier is known from DE 26 24 412, where a planar circular metal sheet is placed against the lower flank of a ring carrier, bent around the ring carrier so as to assume a U-shaped cross section, placed in pre-turned recesses of the ring carrier, clamped tight, and subsequently welded. As the metal sheet is bent around the ring carrier in the a U-shaped form, it is possible to obtain a substantial undercut between the metal sheet cooling duct and the ring carrier. The drawback of this method is the handling of the metal sheet during bending, which is limited by the ring carrier, and the fact that the metal sheet has to be clamped tight before it is welded. Furthermore, it has been found that it is not possible to safely ensure a pressure-tight connection between the metal sheet cooling duct and the ring carrier, which is a precondition for casting the ring carrier.
Another ring carrier assembly is disclosed in U.S. Pat. No. 4,907,545. In this patent the metal sheet is secured on the ring carrier by welding or soldering. As shown in FIGS. 1 and 4, the metal sheet is butt-joined with the radially inwardly disposed wall, or with the bridges of the ring carrier extending from the wall. In FIGS. 5, 6 and 7, the metal sheet is placed flat against plane or curved surfaces of the ring carrier. All of these embodiments have the common characteristic that prior to welding, the metal sheet has to be shrunk into the ring carrier in a costly manner by temperature differences, or that it has to be clamped tight during welding, and that the cross section of the welding seams are relatively small. This patent also has the drawback that during shrinking with a butt joint, the relatively thin metal sheet is stressed and can buckle.
Ring carrier assemblies of this type are also shown in Japanese Patent No. 05-240347 and European Patent No. 791 723. In these documents, too, the metal sheet forming the cooling duct or channel is either shrunk into the cylinder-shaped, radially inwardly disposed surface of the ring carrier by application of temperature differences, or shrunk into grooves milled into the ring carrier.